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whydontuwannawork t1_ja08cwr wrote

Reply to comment by Chiperoni in Would two people who look identical but who are not related have similar matching DNA? by OhMyThiccThighs

So like getting the same answer in math using a different method?

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Hagenaar t1_ja0h405 wrote

Another analogy is convergent evolution. Wherein creatures that look similar, and occupy similar ecological niches may have come from very different forebears.

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helvetica_simp t1_ja18ql2 wrote

Like how raccoons have little hands and humans have little hands? 🥺

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Hagenaar t1_ja1bvsv wrote

That could be more of a divergence given we're both descended from small furry mammals.

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AilisEcho t1_ja1j9ko wrote

What about kangaroo and deer having similarly built heads?

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r0botdevil t1_ja22myi wrote

A much better example is penguins, dolphins, and sharks all having very similar appendages for swimming, or birds, bats, and butterflies all having wings.

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tatu_huma t1_ja34wbs wrote

Australia is a good continent for this since it been so isolated from the rest of the world for so long there's been time for convergence.

They look so similar to animals outside of Australia.

Here's a graphic showing them

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SeenWhatMakesUCheer t1_ja2kht7 wrote

Crabs, nature wants to often form crab looking creatures from different origins

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ThrillSurgeon t1_ja2efh6 wrote

Still, it probably is mathematically possible to a degree, but probably statistically in the domain of one solid object passing through another solid object because the subatomic particles lined up. Although, probably more likely than that.

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Unicorn_Colombo t1_ja0e23x wrote

Yes. Phenotype is a function of genes. So p = f(g). Obviously, it depends on the function f. If the function was an absolute value, then g = 2 and g = -2 both will give you same phenotype 2.

Back from math and into biology, in many mendelic traits, which are traits where a phenotype depends on a single gene, the receive allele is simply an allele that does not produce a particular product, such as a pigment. Such as blue eyes, which are eyes that lack melanin (the eye colour is not a perfect example, as it turns out it is not exactly mendelian trait, but lets assume for simplicity it is).

Obviously, if a gene is not producing a certain product, a protein that is directly involved in some pathway, it is because it is "damaged" in some way. And there are many way it might be damaged. A protein might be produced, but it is non-functional, shorter, or the protein might not be produced at all. So many different mutations might be responsible for the same trait.

When we look at polygenic traits like height, we will see many different genes that are responsible for a small difference in height. When you plot the population phenotype, you might see a normal distribution. Consequently, assuming the same difference for every gene and 100 genes and an on/off effect of a particular gene, you can get a trait resulting from 50 genes in many way (something like 10^29 combinations).

On top of all this, traits depend on an environment. In the case of height, this is only a potential, you will benefit from your genotype only if you will have plenty of nutrition in your young age to reach this potential.

This difference between genotype and phenotype for polygenic traits, and the effect of an environment, is important when doing a selection in agriculture. Trying to find out how much of the trait is hereditary and how much it is determined by genetics gives you an estimate on how much you can influence the trait by breeding.

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This_is_a_monkey t1_ja0ysmv wrote

Building identical houses using completely different materials. You can't tell unless you inspect very closely

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